So much for my hope of reading something else into the fact that Williams had not officially signed yet. He's now signed up and officially a Celtic. Via the team press release:
The Boston Celtics announced today that the club has signed free agent center/forward Shelden Williams to a contract. Per team policy, terms of the deal were not disclosed.
Williams, a 6'9", 250 lbs center/forward, was originally drafted with the fifth overall pick in the 2006 NBA Draft by the Atlanta Hawks. The former Duke Blue Devil has posted career averages of 4.7 points and 4.2 rebounds in 14.7 minutes per game. After being acquired by the Minnesota Timberwolves from the Sacramento Kings on February 19, 2009, he appeared in 15 games for his new team and averaged 4.9 points and 5.0 rebounds in 13.8 minutes per game.